Long Vowel

Compensatory lengthening in phonology and historical linguistics is the lengthening of a vowel sound that happens upon the loss of a following consonant, usually in the syllable coda, or of a vowel in an adjacent syllable. Lengthening triggered by consonant loss may be considered an extreme form of fusion (Crowley 1997:46). Both types may arise from speakers' attempts to preserve a word's Moraic Weight

An example from the history of English is the lengthening of vowels that happened when the voiceless velar fricative /x/ and its palatal allophone [ç] were lost from the language. For example, in the Middle English of Chaucer's time the word night was phonemically /nixt/; later the /x/ was lost, but the /i/ was lengthened to /iː/ to compensate, causing the word to be pronounced /niːt/. (Later the /iː/ became /aɪ/ by the Great Vowel Shift.)

Explanation

Loss of Consonants

Definition

Loss of consonants is a historical sound change in which one or more consonants that were once pronounced gradually disappeared from speech. As these consonants were lost, the preceding vowel often became longer, and after the Great Vowel Shift, many of these long vowels changed into the pronunciations we hear today.

In other words:

Consonant disappears
        ↓
Vowel lengthens
        ↓
Great Vowel Shift
        ↓
Modern English pronunciation

Example 1: night

The gh originally represented the velar fricative /x/ (similar to the sound in German Bach or Scottish loch). When this consonant disappeared, the preceding vowel lengthened and later shifted from /iː/ to /aɪ/.

More examples

Multiple consonants lost

Some words lost more than one consonant.

knight

The following consonants disappeared:

• Initial k
• Medial /x/ (written gh)

Only the spelling preserves their existence today.

write

The initial w was once pronounced but later became silent.

lamb

The final b was originally pronounced but later disappeared.

Common silent letters caused by historical consonant loss

*Some silent letters (such as b in debt) were restored in spelling because of Latin influence rather than natural sound change.

Why this matters

Many irregular English spellings make sense once you know that the spelling often preserves older pronunciations.

For example:

• gh in night is not random—it once represented a real consonant.
• k in knife was once pronounced.
• w in write was once pronounced.

Modern English spelling is therefore a record of the language's history rather than a perfect guide to its pronunciation.

Key Takeaways

• Loss of consonants is a historical sound change, not a modern pronunciation rule.
• The disappearance of consonants often caused the preceding vowel to lengthen.
• Many of these long vowels later changed again during the Great Vowel Shift.
• Silent letters such as gh, k, w, and b are often remnants of these historical pronunciations.